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Contribution of the study of acetabulum for the estimation of adult subjects.

INTRODUCTION: The study of the posterior part of the pelvis is of interest in forensic anthropology since it is an anatomical region that is very often preserved. The Lovejoy technique, using the auricular surface has brought about many studies and attracted many authors, among them Buckberry and Chamberlain utilized the criteria described by Lovejoy and developed new methods. By using this research as a starting point, we have described acetabular criteria. The goal of this study was to test these criteria and to link them to auricular surface reading criteria, as described by Buckberry and Chamberlain. METHOD: The study concerned 52 pelvises of known age and sex. We studied the age correlation of various criteria read at the acetabulum level and that of the auricular surface. We then went on to draw up scores and established a correlation of these scores with age. Intra- and inter-observer variability was also studied. We used the SPSS software package for statistical analyses. DISCUSSION: We were able to isolate four acetabular criteria and four auricular surface criteria which have a correlation with age. Establishing these scores (sum of criteria) allows a better age-based correlation to be obtained. Establishing an overall score, including acetabular criteria and auricular surface criteria, allows a good level of correlation to be obtained with age, with low intra- and inter-observer variability. CONCLUSION: The study of acetabulum is of interest for the age estimation of adult subjects. The joint study of the acetabulum and the auricular surface allows a higher correlation with actual age to be obtained. This study must be broadened to include a wider sample so as to allow fine-tuning of a method.

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Histologic changes in the dog acetabulum following total hip replacement with current cementing techniques.

Histologic changes in the acetabuli of adult dogs were studied following total hip replacement with current cementing techniques. Active bone remodeling was evident throughout the acetabulum by 2 weeks after operation and continued throughout the 6 months of the study, leading to considerable hypertrophy of the trabecular bone of the acetabulum. By 6 months after operation, a thick (average, 0.4 mm), fibrous membrane had formed at the bone-cement interface in 83 of 84 sections examined. Direct apposition of bone to cement was seen only within the 2-mm fixation holes. Formation of a fibrous membrane appears to be intrinsic to the cementing of the acetabular component, perhaps because geometry of the acetabulum precludes effective pressurization of the cement.

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[3D-CT and angiography of cast preparations of pelvic vessels: demonstration of arterial blood supply of the acetabulum].

Anatomical studies of the arterial blood supply of the acetabulum were performed utilizing conventional angiography and 3D-CT on 27 hip specimens. In 16 cases the arterial arborization was filled with undiluted barium-sulfate via the internal artery and in 11 cases with a solution of resin and lead power. 3 specimens out of 30 were excluded because of extravasation using barium-sulfate in one case and incomplete filling with resin in 3 cases. Conventional angiograms were performed in all specimens and in preparations with resin/lead power additional three-dimensional reconstructions of the surface of the acetabulum and arterial cast were done with 3D-CT. 3D-CT shows precise relationship of the arteries to the acetabulum in any spatial plane and definition of vascular supply without elaborate preparation. 3D-CT is superior to non-selective conventional angiography because of better definition of arterial arborization. Filling with resin and lead powder is optimal for anatomical studies because of its reliability and stability. It permits comparative 3D-CT and conventional x-ray examination and subsequent preparation of the vessels in corrosion technique. The advantages of 3D-CT in vessels of cadaver specimens should encourage research on its viability in patients.

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[Spherical calculation of the contact surface between the acetabulum and femur head].

A template for calculating the contact area between the femoral head and the acetabulum is described. The projected image of a sphere is divided into segments of equal surface areas, each segment comprising 0.5% of the total surface area of the sphere. By adding the segments and multiplying the resulting percentage by the total surface area resulting from the radius of the sphere, any partial area of the sphere can be calculated. It is thus possible, without any special mathematical knowledge, to calculate the contact area between the femoral head and the acetabulum, as well as any partial surface area relevant to loading of the joint, on the a.p. roentgenogram. A prerequisite for this is a sufficient area of spherical femoral head in the region in question. In addition, the template can also be used to calculate the biomechanically relevant angle between the frontal plane, set through the center of the femoral head, and the anterior limit of the acetabulum, on the a.p. roentgenogram of the hip.

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[Osteochondrosis and osteochondronecrosis of the roof of the acetabulum].

Osteochondritis of the centers of ossification is a frequent condition during pubertal growth spurt. The ossification of the acetabulum is completed during that period by fusion of the primary and secondary ossification centers (Os acetabuli etc.). During that time of maximal longitudinal growth the pressure within the hip joint can impair the formation of the acetabulum. Usually the acetabular roof is involved to a lesser degree and spontaneous healing of the changes is observated (grade I). Under biomechanically disadvantageous conditions (e.g. coxa valga et antetorta) marginal defects of the acetabular roof (grade II) or even secondary dysplasias of the acetabulum are possible. From long term observations we come to the conclusion, that the pubertal growth spurt is a critical period for the development of the adolescent hip joint.

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Correlation between center-edge angle and acetabulum-head index in developmental dysplasia of the hip with avascular necrosis of the femoral head.

In order to clarify the relationship between the center-edge angle and the acetabulum-head index, we reviewed 97 hips in 86 patients suffering from developmental dysplasia of the hip. We measured the center edge angle and the acetabulum-head index, and evaluated avascular necrosis of the femoral head according to Kalamchi classification. The center-edge angle correlated highly with the acetabulum-head index in non-avascular necrosis, and in Kalamchi groups I and II, but not in Kalamchi groups III and IV. Because of difficulties in measurement, it is possible that the center-edge angle does not precisely indicate acetabular coverage of developmental dysplasia of the hip with avascular necrosis.

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Acetabulum-head index measured on arthrograms in children with Legg-Calvé-Perthes disease.

The acetabulum-head index (AHI), which can be used to assess the lateral displacement of the femoral head, was measured on both plain radiographs and arthrograms in 37 children with unilateral Legg-Calvé-Perthes disease. For the identification of the outermost part of the acetabulum on the arthrograms, two measuring points were used: A. the lateral border of the bony acetabulum (arthrogram I) and B. the lateral border of the labrum (arthrogram II). The reproducibility of the measurements, evaluated by duplicate calculations of the AHI on arthrogram II, which was obtained from the unaffected hips, was high; the root mean square error of the AHI was 3.3. On the plain radiographs, an AHI of 80 or less could be used as a 'guideline' to reveal early subluxation of the femoral head. The corresponding figures on arthrograms I and 11 were 70 and 85, respectively.

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Development of the acetabulum and hip: computed tomography analysis of the axial plane.

Acetabular growth and development in the axial plane was evaluated by computed tomography (CT) scan. One hundred seventy normal hips of children ranging in age from 6 months to 17 years were evaluated for axial acetabular index, anterior and posterior center-edge angles (CEA), and acetabular anteversion. The acetabulum deepens and becomes increasingly spherical with time until the age of 13 years. Little further change in acetabular shape occurs once the triradiate cartilage closes. Closure ensues between the ages of 11 and 13 years, occurring slightly earlier in girls. Posterior bony coverage of the femoral head is greater than anterior coverage at all times. Acetabular anteversion showed little change as the acetabulum developed. Establishing normal values for axial development of the hip and acetabulum allows a better three-dimensional concept of the different pathologic conditions and aids in treatment planning.

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Automated segmentation of acetabulum and femoral head from 3-D CT images.

This paper describes several new methods and software for automatic segmentation of the pelvis and the femur, based on clinically obtained multislice computed tomography (CT) data. The hip joint is composed of the acetabulum, cavity of the pelvic bone, and the femoral head. In vivo CT data sets of 60 actual patients were used in the study. The 120 (60 x 2) hip joints in the data sets were divided into four groups according to several key features for segmentation. Conventional techniques for classification of bony tissues were first employed to distinguish the pelvis and the femur from other CT tissue images in the hip joint. Automatic techniques were developed to extract the boundary between the acetabulum and the femoral head. An automatic method was built up to manage the segmentation task according to image intensity of bone tissues, size, center, shape of the femoral heads, and other characters. The processing scheme consisted of the following five steps: 1) preprocessing, including resampling 3-D CT data by a modified Sinc interpolation to create isotropic volume and to avoid Gibbs ringing, and smoothing the resulting images by a 3-D Gaussian filter; 2) detecting bone tissues from CT images by conventional techniques including histogram-based thresholding and binary morphological operations; 3) estimating initial boundary of the femoral head and the joint space between the acetabulum and the femoral head by a new approach utilizing the constraints of the greater trochanter and the shapes of the femoral head; 4) enhancing the joint space by a Hessian filter; and 5) refining the rough boundary obtained in step 3) by a moving disk technique and the filtered images obtained in step 4). The above method was implemented in a Microsoft Windows software package and the resulting software is freely available on the Internet. The feasibility of this method was tested on the data sets of 60 clinical cases (5000 CT images).

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Stress fractures of the acetabulum in 26 racing Greyhounds.

Acetabular fractures in 26 racing Greyhounds were reviewed. All fractures occurred during racing or training and were unrelated to any external trauma. All fractures had similar configurations, were minimally displaced, and involved only the acetabulum. Affected dogs were young (16-36 months). Fractures occurred unilaterally (22 dogs) and bilaterally (4 dogs). There was no sex predilection, and both right and left sides were equally represented. Bilateral fractures were associated with retraining between the occurrence of the first and second fractures. Radiographically, a fracture line was consistently visible in the caudal third of the acetabulum. Fractures in gross specimens resembled an inverted "Y." Results of histologic evaluation of two fractured acetabula showed changes characteristic of a nonunion fracture. Microfractures were evident in the grossly normal acetabulum opposite the fractured side. Evidence obtained from this study suggests a common pathogenesis of the fractures related to tremendous repetitive stresses produced during running. Greyhounds with unilateral acetabular fractures may provide a reproducible model for future studies of stress fractures in animals and humans because of the high incidence of bilateral fractures that develop during retraining. Surgical repair of the acetabular stress fracture was more successful than conservative management in returning the dogs to competitive racing.

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Biomechanical consequences of fracture and repair of the posterior wall of the acetabulum.

We measured the distribution of contact area and pressure between the acetabulum and the femoral head of cadaveric pelves in three different conditions: intact, with an operatively created fracture of the posterior wall, and after anatomical reduction and fixation of the fracture with a buttress plate and interfragmentary screws. The study involved eight cadaveric hip joints from five pelves loaded to 2000 newtons in simulated single-limb stance. Measurements were made with pressure-sensitive film. The acetabulum was divided into three areas--the anterior wall, the superior aspect, and the posterior wall--for the analysis of the data. Creation of a fracture of the posterior wall was followed by an increase in contact area, maximum pressure, and contact force in the superior aspect of the acetabulum. A concomitant decrease in these parameters was observed in the anterior and posterior walls. Anatomical reduction and fixation of the fracture with a plate and screws did not restore the pattern of loading to pre-injury levels.

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Relationship between the sphericity of femoral head-acetabulum and the low incidence of primary osteoarthritis of the hip joint in Koreans.

UNLABELLED: I examined the sphericity and the congruity of the femoral head and the acetabulum in 172 Korean fetuses and in 655 Korean adults. I found that Korean fetal acetabuli and femoral heads are spherical and that the proportion of the head contained in the acetabulum remains constant and congruous throughout the fetal life. Adult actabuli and femoral heads are also spherical in both gender and are there are no visible changes in the shape of the acetabuli and the femoral heads with respect to age. No evidence was found that the congruity of the hip joint is a cause of osteoarthritis of the hip joint. CLINICAL RELEVANCE: Stable hip joints at the time of birth provide an explantation for the low incidence of congenital dislocation of the hip joint in Koreans. The spherical femoral head and acetabulum (congruous hip joint) seem to be a contributing factor to the low incidence of primary osteoarthritis of the hip in Koreans.

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The effect of early anterior approach open reduction with functional postoperative treatment on the early development of the acetabulum in CDH.

Between 1980 and 1983, 30 anterior approach open reductions were performed on congenitally dislocated hips of 29 patients after unsuccessful conservative treatment; patients were between 6 and 18 months old. After the removal of the obstruction from the acetabulum, the reduction was performed with preservation of the limbus. Some part of the capsule was removed to constrict and tighten it and to prevent redislocation. This capsuloplasty demonstrates the success of a Pavlik harness and abduction splint postoperatively, without plaster fixation. The accelerated development of the acetabulum could be observed on radiograph by this functional treatment, compared to the control group treated with the usual hip spica postoperatively. The development of the acetabulum on the operated side almost equals the sound side within a year. If the operation was performed earlier, joint development would be quicker.

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Prenatal development of the human pelvis and acetabulum.

The prenatal development of the human pelvic bone and acetabulum has been studied by means of classical histology and microradiography. The embryonic phase leads to a fully developed hip within 8 weeks of gestation. The fetal period is a growth phase, including the following main features: endochondral ossification of the ilium from the ninth week, asymmetrical development of the iliac shaft from the fifteenth week, "chondroid-like" tissue formation above the acetabulum from the twenty-sixth week and haversian bone remodelling from the twenty-eighth week. The fetal development of the pelvis and acetabulum seems to be highly related to mechanical stimuli, the most important being the gluteal muscular activity and the simultaneous pressure of the femoral head.

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[Analysis of the acetabulum anterior cover].

PURPOSE: The false profile X-Ray view as described by Lequesne, allowing the measurement of the anterior cover of the acetabulum, is a slantwise view obtained by a 65 degrees inclination of the pelvis on the radiographic plate. The errors introduced by this radiological measurement of the anterior cover are evaluated. MATERIALS AND METHODS: An anatomical and radiological analysis is conducted on 20 acetabula. The anterior cover is measured on the bone and the A point, the anterior extremity of the acetabular roof, is plumbed. Each pelvis is imaged following the Lequesne method. The VCA angle is measured with the radiological point A described by Lequesne and with the metallic point A as reference. RESULTS: The difference between the anatomical and radiological values of the anterior cover is an average by 11 degrees and undervalues the anatomical value. The deviation is reduced by the application of a trigonometrical formula. A difference between the radiological localisation of A point described by Lequesne and the metallic marker is pointed out. This difference increases when the acetabulum becomes dysplasic. CONCLUSION: The acetabular anterior cover measured with the radiological incidence described by Lequesne undervalues the real value. Moreover, the error increases when the acetabulum is dysplasic.

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Development of the acetabulum in patients with slipped capital femoral epiphysis: a three-dimensional analysis based on computed tomography.

Orientation and shape of the acetabulum were determined by the use of three-dimensional reconstruction of computed tomography (CT) data sets in 22 patients with a total of 30 slipped capital femoral epiphyses. We developed an interactive three-dimensional software program to measure the anteversion and inclination of the acetabulum without projectional and pelvis-tilting errors. Furthermore, we determined the height, width, depth, volume, and surface of the acetabulum as parameters describing the acetabular shape. Comparison of the affected side with the contralateral unaffected hip showed no significant differences for acetabular orientation and shape. The relationship between the degree of the slip and the acetabular orientation was calculated. No correlation was found. Based on the results of this study, we conclude that the slipping of the capital femoral epiphysis has no influence on acetabular development.

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Development of the acetabulum and the acetabular labrum in the normal child: analysis with radial-sequence magnetic resonance imaging.

The degree of acetabular and labral coverage was clarified in children at different positions using radial-sequence magnetic resonance imaging. Scans were performed on 40 hips in 20 normal children (group A, 6-8 years old; group B, 9-11 years old; group C, 12-13 years old) and on 19 hips of 10 healthy adults as controls. The degrees of coverage of the femoral head by acetabulum, acetabular labrum, and both were measured at seven positions at every 15 degrees from anterosuperior 45 degrees via midsuperior to posterosuperior 45 degrees. Coverage of the femoral head by the acetabulum in young children was less than in adults at all positions, but the total coverage including the labrum was greater than in adults. Development of the acetabulum and the acetabular labrum showed differences by position.

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[Morphological analysis of acetabulum bony curved surface].

By using the reverse engineering (RE) technology, the mesh surface model of acetabulum was reconstructed by triangulation. Based on this kind of model, the local morphological analysis (LMA) and global morphological analysis (GMA) could be processed. The fitting minimal quadric surface method was applied to calculate the curvature of any point on the acetabulum bony surface, the local morphological character of its surface could be acquired, and its global surface character could be determined by GMA. The results showed that the acetabulum bony surface is elliptical surface, and its three eigenvalues (lambda1, lambda2, lambda3) relations on the three axes (x, y, z) are as follows: lambda1 is short than lambda2 and lambda3, lambda2 is close to lambda3.

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